1. Field of the Invention
The present invention relates to an IP switch (Internet Protocol switch) for transferring packet data in the lower layer of ATM (Asynchronous Transfer Mode), to an interface circuit and an ATM switch used for that IP switch, and to an IP switch network system.
2. Related Art Statement
At present, IP (Internet Protocol) is widely used as a protocol in computer communication in which data is divided into packets on a computer before transmission. According to the 7 layer model of OSI (Open System Interconnection), IP is the protocol which belongs to the network layer, and, to perform communication between different physical networks, communication is realized through routers.
However, it has been generally pointed out that it is difficult to make the IP router fast and to provide it with mass storage because of the characteristics of IP, and accordingly, even when high-speed lower layers are employed, their capacity can not be utilized sufficiently.
Recently, as a solution to these problems, there has been noted a technique called “IP Switching” proposed in Flow Labeled IP: A Connectionless Approach to ATM (Proc. IEEE Infocom, San Francisco, March 1996). This technique is one that introduces the arrangement of ATM (Asynchronous Transfer Mode) known as a high-speed communication technique into the ordinary IP, in an attempt to speed up the IP router.